The House of Lords last night rejected an attempt to change the controversial imposition of a 28-day limit on police powers to detain terrorist suspects without charge when peers turned down a 60-day limit offered as a compromise instead of the 90 days originally sought by Tony Blair and Charles Clarke.

After an impassioned debate on the terror bill which saw expert opinion deployed on both sides, the peers voted by 210 to 108 against a Labour amendment which sought to insert the 60-day option, partly on the grounds that the Commons never considered it in November when a Labour revolt helped bring about a 33-vote majority for 28 days.

"The more I have considered, the more I have read, the more I have heard, the more convinced I am the number is somewhere between 28 days and 90 days," the Labour peer Lord Sewel, an academic economist, told the Lords when he moved the amendment on the bill's report stage.

Lord Sewel argued: "Today terrorism is based on a corrupt and perverted fundamentalism which is as much an enemy of the liberal state as the fascism and communism of the last century."

New technology and new terrorist techniques meant the police need more time to investigate alleged terror plots, he said.

His case was backed by peers who included Lady Parks and Lady Ramsay, both former MI6 officers, and by one former head of the Metropolitan police, Lord Imbert, who said that judges would be "suitably robust" in defending suspects' rights.

But the cross-party coalition of peers which opposed the longer period as unwise and unhelpful included Lord Condon, another ex-Met police chief, who said it was not worth "the risk" in extending beyond 28 days. Senior ex-law lords said the same. Labour peers joined Tories and Liberal Democrats in attacking the proposal and Lord Joffe, a crossbench peer, drew criticism from Labour loyalists such as Lady Symons for suggesting that Britain was now introducing measures that resembled apartheid in South Africa.

The Tory spokesman, Lord Henley, told peers: "We believe it is wrong in principle. It is equivalent to a six months custodial sentence and tantamount to imprisonment." Lord Thomas of Gresford, the Lib Dem spokesman, said: "We must not introduce imprisonment without trial in the face of tyranny."